SINT MAARTEN/CARIBBEAN - Invest 99-L is barely hanging on as an upper level low pressure system just to the north of the disturbance is imparting 20-25 knots of wind shear over Invest 99-L, Crown Weather reported on Thursday.
“Satellite derived wind data indicates that there is no well-defined center of circulation with Invest 99-L and instead there is a sharp trough of low pressure associated with Invest 99-L. That upper level low pressure system that is located to the north of Invest 99-L is limiting the amount of development Invest 99-L can undergo. As long as that upper level low pressure system hangs around, we will see little or no tropical development from Invest 99-L.
“A majority of the model guidance, including the European model which had previously been forecasting tropical development, do not forecast any sort of tropical development from Invest 99-L. The reason for this is because the interaction with that upper level low pressure system will just be too much for Invest 99-L.
“The exception to this is the Canadian model guidance which forecasts that Invest 99-L will develop into a tropical storm by Sunday near the northern Bahamas. From there, the Canadian model guidance forecasts that Invest 99-L will curve north and northeast just east of the Carolina coastline during Monday and Tuesday as a tropical storm,” Crown Weather reports.